Spirometric reference values for children and adolescents from Kazakhstan

Stochastic risk assessment of urban soils contaminated by heavy metals in Kazakhstan

Kazakhstan's growing economy has been posing a threat to the natural environment in the country. The study aimed to investigate the status of soil contamination by five heavy metals (Pb, Cd, Cu, Zn, and Cr) in Kazakhstan during 2010-2018 as well as its impact on the population. Data for the analysis were collected from the governmental monitoring agency, which has reported the concentrations of five heavy metals in the Kazakhstan soil each year. Preliminary screening suggested the four most contaminated cities (Balkhash, Ust-Kamenogorsk, Ridder, and Shymkent). Mean soil concentrations in these cities varied between 251 and 442 mg/kg for Pb, 5-9 mg/kg for Cd, 8-138 mg/kg for Cu, 87-178 mg/kg for Zn, and 2-5 mg/kg for Cr. Analysis of geo-accumulation index pointed out the possible anthropogenic origin of the contamination by Pb and Cd in these cities (mean I_geo was 3.81 for Pb and 3.45 for Cd). Further probabilistic risk assessment for these cities demonstrated that mean hazard indices for children fluctuated between 1 and 2 in two cities (Shymkent and Balkhash), whereas cancer risks for both age groups stayed in the range of 1 × 10^-6 and 5 × 10^-6, indicating that soil remediation is urgently required for the health of the citizens and environments. Both ~60-90% of adults and ~30-60% of children cases exceeded the threshold of carcinogenic assessment (1 × 10^-6), suggesting that a large portion of the population in these cities could be affected by heavy metals in soil. The study provides background understanding for decision making on remediation actions and environmental policy and hazardous waste management in Kazakhstan.

Spirometry in Central Asian Lowlanders and Highlanders, a Population Based Study

Introduction: The purpose of the study was to establish spirometric reference values for a Central Asian population of highlanders and lowlanders.

Methods: Spirometries from a population-based cross-sectional study performed in 2013 in rural areas of Kyrgyzstan were analyzed. Using multivariable linear regression, Global Lung Function Initiative (GLI) equations were fitted separately for men and women, and altitude of residence (700–800 m, 1,900–2,800 m) to data from healthy, never-smoking Kyrgyz adults. The general GLI equation was applied: Predicted value=ea0+a1× ln(Height)+a2× ln(Age)+b1× ln(Age100)+b2× ln(Age100)2+b3× ln(Age100)3            +b4× ln(Age100)4+b5× ln(Age100)5

Results: Of 2,784 screened Kyrgyz, 448 healthy, non-smoking highlanders (379 females) and 505 lowlanders (368 females), aged 18–91 years, were included. Predicted FVC in Kyrgyz fit best with GLI “North-East Asians,” predicted FEV₁ fit best with GLI “Other/Mixed.” Predicted FEV₁/FVC was lower than that of all GLI categories. Age- and sex-adjusted mean FVC and FEV₁ were higher in highlanders (+0.138l, +0.132l) than in lowlanders (P < 0.001, all comparisons), but FEV₁/FVC was similar.

Conclusion: We established prediction equations for an adult Central Asian population indicating that FVC is similar to GLI “North-East Asian” and FEV₁/FVC is lower than in all other GLI population categories, consistent with a relatively smaller airway caliber. Central Asian highlanders have significantly greater dynamic lung volumes compared to lowlanders, which may be due to environmental and various other effects.

Reference norms for evaluating maximum expiratory flow of children and adolescents of the Maule Region in Chile

BACKGROUND

The norms for evaluating the maximum expiratory flow (MEF) usually are developed according to chronological age and height. However, to date, little research has been conducted using reference values that take into account the temporal changes of biological maturation. The objectives of this study were to (a) compare the MEF with those of other international studies, (b) align the MEF values with chronological and biological age, and (c) propose reference standards for children and adolescents.

METHODS

The sample studied consisted of 3,566 students of both sexes (1,933 males and 1,633 females) ranging in age from 5.0 to 17.9 years old. Weight, standing height, and sitting height were measured. Body mass index was calculated. Biological maturation was predicted by using age of peak height velocity growth (APHV). MEF (L/min) was obtained by using a forced expiratory manoeuvre. Percentiles were calculated using the LMS method.

RESULTS AND DISCUSSION

Predicted APHV was at age 14.77 ± 0.78 years for males and for females at age 12.74 ± 1.0 years. Biological age was more useful than chronological age for assessing MEF in both sexes. Based on these findings, regional percentiles were created to diagnose and monitor the risk of asthma and the general expiratory status of paediatric populations.

Predictive models and spatial variations of vital capacity in healthy people from 6 to 84 years old in China based on geographical factors

The aim of this study was to provide a scientific basic for a unified standard of the reference value of vital capacity (VC) of healthy subjects from 6 and 84 years old in China. The normal reference value of VC was correlated to seven geographical factors, including altitude (X1), annual duration of sunshine (X2), annual mean air temperature (X3), annual mean relative humidity (X4), annual precipitation amount (X5), annual air temperature range (X6) and annual mean wind speed (X7). Predictive models were established by five different linear and nonlinear methods. The best models were selected by t-test. The geographical distribution map of VC in different age groups can be interpolated by Kriging's method using ArcGIS software. It was found that the correlation of VC and geographical factors in China was quite significant, especially for both males and females aged from 6 to 45. The best models were built for different age groups. The geographical distribution map shows the spatial variations of VC in China precisely. The VC of healthy subjects can be simulated by the best model or acquired from the geographical distribution map provided the geographical factors for that city or county of China are known.

Development of reference equations for spirometry in Japanese children aged 6-18 years

BACKGROUND

Spirometry is the most widely used pulmonary function test and the measured values of spirometric parameters need to be evaluated using reference values predicted for the corresponding race, sex, age, and height. However, none of the existing reference equations for Japanese children covers the entire age range of 6-18 years. The Japanese Society of Pediatric Pulmonology had organized a working group in 2006, in order to develop a new set of national standard reference equations for commonly used spirometric parameters that are applicable through the age range of 6-18 years.

METHODS

Quality assured spirometric data were collected through 2006-2008, from 14 institutions in Japan. We applied multiple regression analysis, using age in years (A), square of age (A(2)), height in meters (H), square of height (H(2)), and the product of age and height (AH) as explanatory variables to predict forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV(1)), peak expiratory flow (PEF), forced expiratory flow between 25% and 75% of the FVC (FEF(25-75%)), instantaneous forced expiratory flow when 50% (FEF(50%)) or 75% (FEF(75%)) of the FVC have been expired.

RESULTS

Finally, 1,296 tests (674 boys, 622 girls) formed the reference data set. Distributions of the percent predicted values did not differ by ages, confirming excellent fit of the prediction equations throughout the entire age range from 6 to 18 years. Cut-off values (around 5 percentile points) for the parameters were also determined.

CONCLUSIONS

We recommend the use of this new set of prediction equations together with suggested cut-off values, for assessment of spirometry in Japanese children and adolescents.